Archive for May, 2011

Envision HDI

Sunday, May 22nd, 2011

Envision HDI is an alternative copper deposition process that just works. Deposition or metalization is the basic foundation of a plated through hole structure. The deposition material makes a drilled hole conductive enough to allow copper to be electroplated within the drilled hole. Without metalization there would be no plated through hole. Of course there are several different chemicals available to metalize a non-conductive surface.

Electroless copper deposition was the original chemical process employed by the pcb industry to form this conductive layer. There were many downsides to this process. Chemical cost, time of operation and waste treatment to name just a few. Some of the chemicals used in the overall process are highly toxic. The process has been improved over the years.

Copper deposition was the only option for a number of years until (more…)

Inner Layer Pre-Clean

Sunday, May 15th, 2011

Inner layer processing requires Dry Film Photo Resist to be laminated onto the copper surface. The dry film is resolved into a circuit pattern. Copper we want to keep is protected by the circuit pattern from the etchants used to remove the copper. The bond of the dry film to the copper surface must be strong enough so that the film does not come of when in the etchant chemistry. Copper foil such as RTF, Reverse Treated Foil, are rough enough so that the dry film forms a good bond to the copper as is. Many copper foils are not rough enough or are supplied with a contaminated surface. In these cases the foil must be (more…)